Symmetry is an important mathematical concept that many students learn somewhere between kindergarten and second grade. It serves as the basis for many other mathematical concepts, and builds on a child's instincts to look for balance and order. Since students can best pick up on something when they can relate to it, it is important to use real-life examples, or have the children give examples of where they see symmetry outside of the classroom. When teaching symmetry to first graders, use a few simple guidelines when formulating your lesson plan.

Start the lesson by describing symmetry in shapes like a square, circle or triangle. Define and discuss the line of symmetry, as well as the concept of a shape having more than one line of symmetry. Explain the activities that show students shapes with symmetry, and contrast them with shapes that do not have a line of symmetry.

Cut enough die-cut shapes for each child, and divide them evenly into plastic bags. Give a plastic bag to each child and have them fold the shapes along their line of symmetry. Let them write their name on the back and hang them on a small tree, dubbed a "symme-tree".

Give each child a blank sheet of paper, and have them fold it in half. Use the safety scissors to cut a shape freehand into the paper from top to bottom. Have them unfold the paper to see their symmetrical image.

Give each child a coloring book page with a picture of a ladybug or butterfly. Have them draw a line down the middle of the creature, or do it for them ahead of time. Pass out crayons or colored pencils and instruct them to color the two sides in a symmetrical fashion.

Pass out blank sheets of heavy paper, and have each child fold their sheet in half. Instruct the children to unfold the paper, use finger paint to create a pattern on one side of the paper, then refold the paper. Press the paint onto the blank side of the sheet of paper, then unfold each sheet to see the symmetrical designs created.

Have students give a definition of symmetry to wrap up the lesson. Let them provide real-life examples of symmetry, including shapes, insects, animals or on themselves. Let students give examples of things with more than one line of symmetry, and use this to transition into the next lesson.

Provide an assessment, if desired, with pictures of shapes or objects that were covered in the lesson. Have the students write "Yes" or "No" to specify whether the given object is symmetrical or not. In another section, have them draw the lines of symmetry on a given object or shape.